Many people want a serialized proto to canonically represent the contents of that proto. Use cases include: using a serialized proto as a key in a hash table taking a fingerprint or checksum of a serialized proto comparing serialized payloads as a way of checking message equality Unfortunately, protobuf serialization is not (and cannot be) canonical. There are a few notable exceptions, such as MapReduce, but in general you should generally think of proto serialization as unstable.
